Circuit interrupter



March 1953 R. MEISENHEIMER ETAL 2,630,503

CIRCUIT INTERRUPTER Filed April 26, 1951 Inventors: Robert L.Meisenheimen Sidneg Rsmithflr'.

b3 Their" Aboorneg.

Patented Mar. 3, 1953 CIRCUIT INTERRUPTER Robert L. Meisenheimer andSidney R. Smith, Jr., Pittsfield, Mass., assignors to General ElectricCompany, a corporation of New York Application April 26, 1951, SerialNo. 222,981

Claims.

This invention relates to electric circuit interrupting devices and moreparticularly to a new and improved arrangement whereby a load circuit inwhich such a device is installed may be manually opened while underload.

This function has been carried out in the case of a conventional fusecutout type of device by the employment of a switch stick to disengage amovable contact on the device from a stationary contact, in other words,by opening the fuse holder in a similar manner to opening a disconnectswitch. However, when the load on the circuit is of sufficiently highmagnitude, a long are is thereby drawn and, under these conditions,harmful fiashovers between adjacent parts frequently occur. Thus,various arrangements involving the employment of levers which may beengaged by the switch stick have been incorporated on such cutouts tomanually break or rupture a fuse link, and thereby interrupt the loadinside a fuse tube, in a manner similar to a normal fuse blowingoperation. However, all such prior art lever arrangements known toapplicants possess objectionable features which it would be desirable tocorrect if at all possible. For example, in the case of one sucharrangement, the application of a fuse link rupturing force by a switchstick to a fuse link rupturing lever tends to separate a movable contactat the top of the fuse tube from a stationary contact, which can only beavoided by the employment of a relatively complex and therefore costlylocking arrangement to maintain the contacts in engagement. Thisdisadvantage has been overcome in another case where a lever arrangementis so provided that the fuse link rupturing force is applied to thelever in an upward direction, which also tends to maintain the upperseparable contacts in engagement. The application of an upward force,however, is objectionable in that the switch stick is more liable toslip off the rupturing lever and a downward pull with a switch stick isa much more normal movement for the operator. In addition, the area orsurfaces presented by these prior art levers tend to reflect the arcgases upward and cause fiashover. Moreover, these lever arrangements arenot attachments but are part of the fuse holder or the fuse holdersupport so that a purchaser can only obtain them by buying a completefuse holder or cutout.

It is therefore an object of our invention to provide an improved fusecutout, incorporating auxiliary structure which will permit the manualinterruption of a circuit while under load.

It is also an object of our invention to provide an arrangement inconnection with which a downward force or pull may be applied to a fuselink rupturing lever, whereby the resulting force on the cutoutstructure tends to maintain separable contacts thereof in engagement.

It is a further object of our invention to provide a relatively simplelever arrangement presenting a minimum surface area.

It is still a further object of our invention to provide a fuse linkrupturing device in the form of a simple, low cost attachment that maybe simply and quickly applied or connected to existing fuse cutouts.

The invention will be better understood from the following descriptionwhen taken in connection with the accompanying drawing, and the scope ofthe invention will be pointed out in the appended claims. In thedrawing, Fig. 1 is a side elevation, partly in section, of a fusedisconnecting switch or cutout embodying the invention and shown in thecircuit closed position; Fig. 2 is a front view of the lower portion ofthe Fig. 1 device; and Fig. 3 is a perspective view of the fuse linkrupturing attachment of our invention.

For the purpose of illustration, we have shown in the drawing an opentype fuse cutout in which the numeral IQ identifies a main support ofporcelain or other similar insulating material of a size and shape usedin connection with the fuse cutouts of the prior art. Insulating supportIt may be suitably mounted on a pole, not shown, in a conventionalfashion, one manner of which is by a supporting arm or bracket H, oneend of which is cemented internally within the support Iii. Adjacent oneend of the insulator H3 and supported therefrom so as to extendtransversely of the insulator is a first relatively stationary contactmeans I2, such as a leaf contact spring, in conducting relation with aline terminal i3. Supported from the opposite or lower end of theinsulator, in line with the longitudinal axis thereof, is a hinge meansor hook-type bearing member M. A second relatively stationary contactmeans 15 in conducting relationship with a terminal it is suitablymounted on bearing member M. To serve as a support for an expulsion"tube il, a hinge element is of conducting material is provided havingtrunnions I 9 adapted to be inserted in the hooks 20 of the bearingelement M. Hinge element or support It is also provided with a contact2! movable into and out of engagement with contact means [5 uponrotation of the hinge element. For completing a conducting path betweenthe stationary contact means l2 and i5 and consequently the terminals l3and It, a current conducting means is provided and comprises a conductor22 having a portion 23 fusible at currents above a predetermined value.Conductor 22, including fusible portion 23 which is also relatively weakmechanically, is mounted within the expulsion tube I"! with one end ofthe conductor suitably connected electrically to a conducting cap 24,threadingly mounted on the upper end of tube l1 and engageable withstationary contact means I 2. As shown, the tube l I is directly mountedon an upwardly extending portion 25 of hinge element support I8 by asplit clamp 26, which in turn is pivotally mounted at 21 on the hingesupport element l8, constituting therewith a toggle which is held in therigid condition shown by pulling the end of conductor 22 which extendsout of the bottom open end of tube [1, transversely thereto, toward aportion of hinge support It where it is secured in any suitable mannersuch as clamping it between the hinge element and a nut 28, which may bedrawn tight by a screw 29. The hinge element or support ['3 and theexpulsion tube ll including the contact at one end thereof whichtogether are all rotatable about the hinge point I 9 comprise what isconventionally referred to in the industry as a fuse holder assembly.For maintaining the switch or fuse holder assembly in the closed circuitposition shown in the drawing, there is provided a holding means whichmay be of any conventional type, such as the one illustrated, whichcomprises a U-shaped resilient member 30, the outer ends of the legs ofwhich are bent inwardly and then outwardly to provide, in v-shapedformation, flared ends which yield sufficiently to permit entrance ofcontact cap 24 and thereupon close over the cap to restrict reversemovement. U-shaped holding member 30, terminal l3, leaf contact spring I2, and, in addition, a leaf backing spring l2, are all carried by abracket 3! extending outwardly from insulator l and supported therefromon a stud 32 mounted in the insulator.

The fuse tube I1 is made from or is lined with a material which willgive off an arc extinguishing gas when subjected to the heat of an arc.Consequently, in the event of a current through conductor 22 in excessof the rating of fusible element 23, this element will rupture,whereupon the lower portion of conductor 22 will begin to dropdownwardly through tube l1, thereby establishing an are which willpromptly be extinguished by the gas given off from the tube. In thismanner, the portion of the circuit in which the device is installed maybe opened or automatically isolated from the balance of the system as iswell known in the art. In addition, the switch may be manually opened byinserting the hooked portion of a switch stick in an operating eye 33,mounted on the fuse tube H, to separate movable contact 24 fromstationary contact L 2. However, as previously pointed out, thissometimes results in a long are being drawn between these two contacts,which is diflicult to extinguish and which may flash to adjacent partsor equipment with adverse results.

As thus far described, the cutout is similar to a type well known in theelectrical industry. However, to manually open the device and at thesame time realize the benefit of the arc extinguishing gas given off bythe fuse tube ll, we have, in accordance with our invention, provided animproved means whereby the conductor 22 may be manually broken orruptured at the fusible or relatively mechanically weak section 23.

This means is very simple in that it comprises only three elements, abar of metal 34, and a lever 35 of round rod or wire of sufiicientstrength, and a rivet or bolt fastening means 38. The bar 34 ispivotally or fixedly mounted at one end on clamping bolt 36 between thetwo halves of clamp 26, as better shown in Fig. 2. Lever 35 is pivotallymounted by means of an eye 3! and bolt or rivet 38 at the opposite orlower end of bar 34 adjacent the lower open end of the expulsion tube[1. A relatively large eye 39 has been formed at the opposite end oflever 35 to conveniently accommodate the hook portion of a switch stick.Lever 35 is otherwise bent, as better illustrated by Fig. 3 at 40, toclear the expulsion tube I! with a portion 4| extending under andtransversely across the open end of tube l1, and the remaining portion42 extending normally to portion 4| and of sufficient length so that theoperating end of the lever or eye 39 will be positioned on the oppositeside of the hinge axis or trunnions 29 from the expulsion tube H when inthe position shown in Fig. 1. In the course of assembling or replacing afuse link, it will be understood that the conductor 22 thereof extendingout of the lower open end of the tube is merely looped around theportion 4| of lever 35, and fixed to the hinge support element aspreviously described and as illustrated.

When it is desired to manually break the fuse link within the expulsiontube, a downward force or pull is applied to the eye 39, whereby a forceseveral times the applied force is imposed upon the fuse link to effectrupture thereof, and withdrawal of conductor 22 from the open end of thefuse tube. Inasmuch as the expulsion tube, expulsion tube support orhinge element and fuse link may be considered for all practical purposesas a unitary mass at any time prior to actual rupture of the fuse linkand since the operating force applied to lever 35 is to the left of thehinge point while the pivot point of the lever or point of applicationof the reactive force is applied to the mass on the opposite side of theexpulsion tube axis from the hinge point, it will also be apparent thatthe resulting force on the structure is such as to rotate the expulsiontube or mass in a counterclockwise direction, as viewed in Fig. 1, aboutthe hinge axis at the trunnions I9, so that there is no tendency for thecontacts 24 and I2 to become separated. Of course, upon rupture of thefuse link but subsequent to extinguishment of the resulting are withinthe expulsion tube, the toggle mounting will collapse allowing contact24 to drop down away from holding member 30 and clockwise rotation ofthe fuse holder assembly.

Thus, we have provided a fuse link rupturing arrangement for fusecutouts, whereby a fuse link may be manually ruptured by the applicationof a downward force to a rupturing lever, but in addition, the improvedarrangement is such that the resulting force on the cutout structuredoes not tend to disengage the normally separable contacts. Moreover,the arrangement comprises a simple attachment which may be simply andquickly applied to existing cutouts. This is an economic advantage tothe user permitting him to purchase and stock standard cutouts, at thesame time being able to apply switching attachments to those particularcutout installations where the load switching requirements arerelatively severe.

While we have, in accordance with the patent statutes, shown anddescribed a particular embodiment of our invention, it will be obviousthat changes and modifications can be made without departing from theinvention in its broader aspects and we, therefore, aim in the appendedclaims to cover all such changes and modifications as fall within thetrue spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. In an electric circuit interrupter, a fuse holder assembly rotatableabout a hinge point comprising an expulsion tube support mounted at saidhinge point, an expulsion tube having a contact at one end thereof, saidexpulsion tube being open at the opposite end and mounted on saidsupport so as to be rotatable about said hinge point, a fuse link withinsaid tube fixed at the contact end thereof and extending out of the openend of said tube, said extending portion of said fuse link being securedto said support and a fuse link rupturing lever pivotally mounted at oneend on said fuse holder assembly on the opposite side of the axis ofsaid expulsion tube from said hinge point, said lever having a portionlocated between said extending portion of said fuse link and the openend of said tube, the opposite end of said lever comprising an operatingloop positioned on the opposite side of said hinge point from said fusetube.

2. In an electric circuit interrupter, a fuse holder assembly rotatableabout a hinge point comprising an expulsion tube rotatable about saidhinge point and having an open end adjacent thereto, a contact mountedat the opposite end of said tube, a fuse link within said tube havingone end thereof connected to said contact and the other end extendingout of the open end of said tube and secured adjacent thereto and a fuselink rupturing lever pivotally mounted at one end on said fuse holderassembly on the opposite side of the axis of said expulsion tube fromsaid hinge point, said lever having a portion positioned above and inengagement with the extending portion of said fuse link, the oppositeend of said lever comprising an operating loop being positioned on theopposite side of said hinge point from said fuse tube.

3. In an electric circuit interrupter, a fuse holder assembly rotatableabout a hinge point comprising an expulsion tube rotatable about saidhinge point and having an open end adjacent thereto, a contact mountedat the opposite end of said tube, a fuse link within said tube with oneend thereof connected to said contact and the other end projecting outof the open end of said tube and secured adjacent thereto and a fuselink rupturing attachment comprising a lever pivotally mounted at oneend on said fuse holder assembly on the opposite side of the axis ofsaid expulsion tube from said hinge point, said lever extending betweensaid open end and said fuse link projecting therefrom, the opposite endof said lever comprising the operating end thereof positioned on theopposite side of said hinge point from said fuse tube.

4. In an electric circuit interrupter, a fuse holder assembly rotatableabout a hinge point comprising a fuse holder tube having a contact atone end thereof and rotatable about said hinge point from a contactclosed to a contact opened position, the opposite end of said tube beingopen and adjacent said hinge point, a fuse link within said tubeconnected to said contact and including a conductor portion projectingout of the open end of said tube and secured adjacent thereto and a fuselink rupturing attachment comprising a lever mounted on said fuse holderassembly on the opposite side of the axis of said tube from said hingepoint and having a portion positioned between said projecting conductorand the open end of said tube, said lever having an operating end forthe application of a fuse link rupturing force positioned on theopposite side of said fuse holder hinge point from said fuse holder tubewhereby the application of a downward force to said operating end ofsaid lever results in a force tending to hold said fuse tube in acontact closed position and a force tending to rupture said fuse link.

5. In a fuse switch having a fuse link within a fuse tube mounted on ahinged fuse tube support and constituting a fuse holder assemblyrotatable about a hinge axis between an open and a closed position withthe fuse link fixed at one end of the tube and extending out of andsecured adjacent the opposite and open end thereof, a fuse linkrupturing attachment comprising a lever mounted for pivotal rotationabout one end thereof on said fuse holder assembly on the opposite sideof the axis of said tube from said hinge axis and having a portionpositioned above and in engagement with the extending portion of saidfuse link, the opposite end of said lever comprising the operating endthereof being positioned on the opposite side of said hinge axis fromsaid fuse tube.

ROBERT L. MEISENHEIMER. SIDNEY R. SMITH, JR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,310,466 Schultz et a1. Feb. 9,1943 2,514,163 Pittman July 4, 1950 2,574,400 Lesher Nov. 6, 1951

